1. Field of the Invention
The present invention relates to a push switch device whose seesaw type movable contacts are moved as a result of pushing down a plunger.
2. Description of the Related Art
A conventional push switch device of such a type is disclosed, for example, in U.S. Pat. No. 4891476, and is shown in FIG. 13.
FIG. 13 illustrates the aforementioned conventional push switch device.
Referring to FIG. 13, reference numeral 51 denotes a top case; reference numeral 52 denotes a push button that is supported at the top case 51 so as to be movable vertically; reference numeral 53 denotes a cam shaft that is inserted into a hole in the push button 51; reference numeral 54 denotes a coil spring; reference numeral 55 denotes a sliding element supporting member that is integrally fitted to the cam shaft 53; reference numeral 56 denotes a wafer with a stationary contact; reference numerals 57 denote terminals led out from a stationary contact; and reference numeral 58 denotes a base,
In the switch device of FIG. 13, pushing the push button 51 against the force of the coil spring 54 causes the cam shaft 53 to rotate with its axial core as center and the sliding element supporting member 55 to rotate. Rotation of the sliding element supporting member 55 causes the sliding element to come into contact with or separate from the stationary contact, whereby an on operation or an off operation is performed.
In such a conventional switch device, however, the cam undergoes wear with use. This results in the production of powder that causes switching operation failure or the like. When medium current is used, an arc is generated during switching of contact connections. This also results in the production of powder that causes electrical connection failure.